Co-Occurrence of Atypical Endometriosis, Subserous Uterine Leiomyomata, Sactosalpinx, Serous Cystadenoma and Bilateral Hemorrhagic Corpora Lutea in a Perimenopausal Adipose Patient Taking Tamoxifen (20 mg/Day) for Invasive Lobular Breast Cancer

BACKGROUND: For women taking tamoxifen, recent data strongly support the estrogen agonist role of tamoxifen as a causal factor for the increased risk of endometriosis, but also of leiomyomata, endometrial polyps, and endometrial hyperplasia. CASE REPORT: A 54-year-old perimenopausal woman on tamoxifen (20 mg/day), gravida 0, with surgically treated invasive lobular breast cancer and extensive lobular carcinoma in situ (pT2 (m) pN0 (snl) pL0 G2 pTis (LCLIS) R0 M0 Ki-67 1%, ER+, PR+, Her-2-neu-negative) was referred for evaluation of a pelvic mass. The ultrasonographic examination showed a regular endometrium of less than 6 mm thickness, a uterine myoma (approximately 3 cm in diameter), a right-sided sactosalpinx (7.7 x 3.6 x 5.7 cm), an ovarian cyst on the right side (approximately 4 cm), and a left-sided ovarian cyst (approximately 3 cm in diameter) without any malignancy criteria. The CA-125 level was normal (9.4 U/ml). With the exception of a decreased serum progesterone level; the endocrine status showed no sign of ovarian insufficiency (LH 5.6 mIU/ml, FSH 9.0 mIU/ml, estradiol 103.7 pg/ml, progesterone 1.51 ng/ml, testosterone 0.11 ng/ml, DHEA-S 62.3 microg/dl, SHBG 64.39 nmol/l, free androgen index 0.6). During laparoscopy 2 uterine subserous leiomyomata, a right-sighted sactosalpinx, bilateral ovarian cysts, and an extended polypoid, vascularized endometriosis of the bladder peritoneum, the pelvic wall and Douglas pouch were found. Complete pelvic deperitonealization, bilateral adnexectomy, and also enucleation of the 2 leiomyomata were performed. RESULTS: Pathological examination confirmed the sactosalpinx. In the cystic ovary (right side), a serous cystadenoma close to a hemorrhagic corpus luteum (HCL) was diagnosed. The left ovary showed another HCL. The removed leiomyomata did not show atypia or significant mitotic activity. The endometriotic lesions presented strong expression of the estrogen receptor, the progesterone receptor, and the proliferation marker MIB-1. In addition, there was no HER-2-neu expression. A switch to the aromatase inhibitor letrozol was recommended. CONCLUSION: The possibility of tamoxifen-induced or tamoxifen-driven endometriosis in peri- or postmenopausal patients with breast cancer should be considered.